Gearing device



April 17, 1956 M. OBERLIN GEARING DEVICE 2 Sheets-Sheet 1 Original Filed Aug. 1, 1949 mjmzmmm um l2 EOPOE INVENTOR. L. M. OBERLIN Wm -r A T TOR Z L. M. OBERLIN GEARING DEVICE April 17, 1956 2 Sheets-Sheet 2 Original Filed Aug. 1, 1949 INVENTOR. L M OBERLIN A 7'TORNEYS United States Patent GEARING DEVICE Lyman M. Oberlin, Dewey, Okla., assignor to Phillips Petroleum Company, a corporation of Delaware Original application August 1, 1949, Serial No. 107,927. Divided and this application March 19, 1951, Serial No. 216,440

6 Claims. (Cl. 318-348) This invention relates to computers. In another aspect, it relates to a computer wherein coefiicients' of the equations to be solved are inserted by adjustment of variable impedance networks and the apparatus thereafter automatically obtains a solution to the equations. In still another aspect, it relates to a gearing device for selectively connecting a plurality of variable impedances to a driving shaft.

This invention is a division of my copending application, Serial No. 107,927, filed August 1, 1949, now Patent No, 2,584,809.

Computers have been developed which are adapted for the solution of simultaneous linear equations, the coefiicients of the equations to be solved being inserted into the computer by adjusting impedances, such as variable resistors, which were connected in an impedance network. Each network was provided with one or more balancing resistors and these resistors were successively adjusted manually to balance the networks, at which time the setting of the balancing resistors represented the solution to the series of linear simultaneous equations. In order to obtain a high degree of accuracy, it was necessary to make several adjustments to each balancing resistor, which was a time consuming operation. In addition, fatigue on the part of the operator and errors in reading the indicator provided for showing a balanced network condition introduced corresponding errors into the solution of the series of equations.

It is an object of this invention to provide a computer which automatically obtains a solution of the equations once the coefficients are inserted into the computer.

It is a further object to substantially reduce the time required in solving simultaneous equations and to elimmate errors in judgment on the part of an operator.

It is still a further object of the invention to provide a novel gearing device for selectively connecting a plurality of variable impedances to a common driving shaft.

It is a still further object to provide a computer which is reliable in operation, and uses a minimum number of standard circuit components.

Various other objects, advantages and features of the invention will become apparent to those skilled in the art from the accompanying disclosure and drawings, in which:

Figure 1 is a schematic circuit diagram of the computer;

Figure 2 is a side elevational view of the clutch device;

Figure 3 is a sectional view taken along the line 3--3 of Figure 2; and

Figure4 is a detail view illustrating a feature of the invention.

Referring now to the drawings in detail, and particularly to Figure 1, the control apparatus of this invention is shown in connection with a computer of the type adapted to solve simultaneous linear equations by the principle of successive iteration. The invention is also applicable to different types of computers, such as com- 2,742,598 Patented Apr. 17, 1956 ice puters for solving simultaneous differential equations. In the example shown by Figure l, the computer is adapted for the solution of four linear simultaneous equations in four unknowns. Each equation of the set is represented by a variable impedance network extending transversely of the sheet upon the drawing. Thus, the setting of variable resistors A-l, B-l, C-l, D-1, and K-1 represents the coeificients of the first equation while the setting of variable resistors A-4, B-2, 0-4, D-4, and K-4 represents the coetficients of the fourth equation, it being understood that the resistor K-4 represents the constant term while resistances A-4, B-4, C-4, and D-4 represent the coefiicients of the variables in the equations. In the present example, a voltage drop is produced across each of the resistances making up the network by a battery 10 and a reversing switch 11, the reversing switch being provided so that polarity of the voltage impressed across the resistance may be changed to represent a negative coefiicient. It will be noted that battery 10 and reversing switch 11 establish a voltage drop across each of the resistances A-1 to A4, inclusive. Similar batteries 10a, 10b, 10c and reversing switches 11a, 11b, are provided for the other variable resistances of the networks. The variable resistors K are connected in circuit with a battery 12 to provide a voltage drop across said variable resistors and each of the batteries has a switch connected in circuit therewith to prevent current flow when the apparatus is notin use.

A plurality of balancing resistors W, X, Y, and Z are connected in circuit with the impedance networks by a multi-gang switch S, the sections of which are shown as 5-1 to S-6, inclusive. When this switch is in position 1, the balancing resistors W, X, Y, and Z are connected in parallel, respectively, with the network re-' sistors A-l, B-l, C1, and D1. When the switch is moved to its other positions, the balancing resistors are connected in parallel with the respective variable resistors of the second, third and fourth networks. It will be apparent that settings of balancing resistors W, X, Y, and Z represent the values of the variables in the system of simultaneous equations to which the computer is applicable. With the switch in position 1, for example, resistor W is connected in cascade with resistor A-1 and, similarly, the other balancing resistors are connected in cascade with the respective network resistors. Accordingly, the voltage drop produced across each set of balancing and network resistors is proportional to the product of their resistances, that is, to the product of the coefiicient and variable represented by the settings of the resistors. The sum of the voltage drops across each set of cascaded resistors and across resistor K-1 appears between leads 13 and 14. When the voltage across these leads is zero, the values of the variables represented by the settings of balancing resistors W, X, Y, and Z are such that the equation is satisfied. When the balancing resistors are not set to values at which the equation is satisfied, an error voltage appears across leads 13, 14 the amplitude of the error voltage being pro portional to the amount by which the variables depart from values which satisfy the equation. Similarly, when switch S is moved to position 2, an error voltage is produced across leads 13, 14 unless the settings of balancing resistors W, X, Y, and Z is such that the equation represented by the settings of variable resistors A-2, B-2, C-2, and K-Z is satisfied.

When the settings of the balancing resistors W, X, Y, and Z are found at which the error voltage is zero as switch S is moved through positions 1 to 4, the values of the variables represented by the setting of the balancing resistors are a solution to the set of equations represented by the four resistance networks in the computer.

In some cases, the sections 5-1 to 8-5 of switch S may be eliminated and a ganged variable resistance may be substituted for each of the balancing resistors W, X, Y, and Z, each section of the ganged resistor being connected in cascade with one of the network resistors. The present invention is also applicable to computers wherein the multiplication of the variables and coefiicient is attained by an Ohms law device. In such a computer, for example, a variable resistance may represent the coefficient, the cur rent through the resistance may represent the variable, and the voltage drop across the resistance represents the product of the variable and coefiicicnt. In all such computers, as well as in many types of computers for solving differential equations, an error voltage is produced unless the electrical quantities representing the variable of the equation are so adjusted as'to balance the circuit, that is, to provide a solution to the equation.

In accordance with the invention, the error voltage appearing across leads 13, 14 is fed to a direct current amplifier 15, the output of which is applied to a reversible direct current motor 16 and the winding 17 of a relay 18 having normally closed contacts 19. The contacts 19 are connected in circuit with a battery 20, a motor 2E. and a switch 22. Switch 22 is desirable to prevent drain on battery 20 when the computer is not in use. The motor 21, in turn, is connected mechanically to the switch S and operates to move said switch successively to its different positions when energized by closure of contacts 19. When an error voltage appears across leads 13 and 14, relay it; is energized and contacts 19 are open with the result that the motor 21 is de-energized. However when the error voltage drops to zero, relay 18 is de-energized with resultant closure of contacts 19, thereby effecting operation of motor 21 to move switch S to its next position.

Reversible motor 16 is selectively coupled to the balancing resistors W, X, Y and Z by the gearing arrangement shown in Figures 2 to 4. This gearing device includes a series of relay coils R-l to R-i which are connected in circuit with a battery 23, a switch 24 and section S-6 of multi-gang switch S. As will become apparent, when coil Rll is energized, motor 16 is connected mechanically to resistor W and, when coils R-2, R-3, and R-d are selectively energized, motor 16 is mechanically connected to the respective balancing resistors X, Y, and Z.

Referring now to Figure 3, it will be noted that reversible motor 16 drives a shaft 25 carrying a gear 26. The balancing resistors W, X, Y, and Z are spaced around the shaft 25 and each balancing resistor is supported in the manner shown by Figure 2; In this figure, it will be noted that balancing resistor W has a control shaft 27 which is carried by slotted supports 28, the control shaft being provided with collars 29 to prevent longitudinal movement of the shaft. so arranged as to allow radial movement of the variable resistor and its control shaft toward and away from the gear 26 carried by driving shaft 25. The control shaft carries a gear 31 which is normally disengaged from gear 26. To this end, the casing of balancing resistor VJ is provided with a pin 32 which is carried by a slotted member 33 projecting from base 34. A spring 35 is mounted between pin 32 and base 34 to urge balancing resistor W and its control shaft radially outward from gear 26. Balancing resistor W also carries an armature 3'7 which is attracted by coil R-l. when the latter is energized, thereby to move balancing resistor W and its control shaft radially inwardly a sutficient distance that gear 31 engages gear 26. Accordingly, balancing resistor W is normally disconnected from gear 26 and reversible motor driving shaft 25. However, when coil R-l is energized, gear 31 engages gear 26 and the reversible motor drives control shaft 27 to change the ohmic value of balancing resistor W. Each of the balancing resistors W, Y, and Z .is similarly mounted and their control shafts have gears 39, ll) and 4t Slots in the supports 28 are which are moved into engagement with gear 26 upon energization of the respective coils R-2, R3, and R4, Figure 1. In somecases, each control shaft 27 may include speed reduction mechanism to afford a finer adjustment of the variable resistance and, of course, worm gears may be utilized both on the driving and driven shafts, if desired. The coils R are mounted on a sleeve carried by shaft 25, this sleeve being held in a stationary position by a support, not shown.

In the operation of the circuit of Figure l, the coefficients of the linear simultaneous equations which it is desired to solve are inserted into the computer by appropriate adjustment of resistances A, B, C, D, and K. With switch S in position 1, coil R-l is energized by battery 23 through switch S6 to connect reversible motor 16 to balancing resistor W and, if the values represented by the setting of variable resistances W X, Y, and Z are not such as to satisfy the equation represented by coefficients A4,, 84., C-1, D-1, and K-1, an error voltage is developed across leads 13 and 14. This error voltage energizes relay 13 and prevents operation of motor 21 so that switch S is not moved to position 2. Reversible motor 16 then moves balancing resistor W until the network is balanced, at which time the error voltage becomes zero. Thereupon, relay i8 is de-encrgized and motor 21 moves switch S to position 2. As a result, coil R-l is deenergized and coil R2 is energized, thus disconnecting motor 16 from balancing resistor W, and connecting it to balancing resistor X. With switch S in position 2, the potential drops across resistors A-2, B2, 0-2, and K-Z are added, the resultant voltage appearing across lead 13, 14. If an error voltage is developed, relay lid is energized to prevent further operation of motor 21 and reversible motor 16 moves balancing resistor X until the network is balanced. It will be noted that balancing resistor W remains at the position to which it was moved by motor 16 as this operation takes place, this setting representing a first assumed value of the variable represented thereby. When the error voltage becomes zero, motor 21 is energized to move switch S to position 3, reversible motor 16 being disconnected from balancing resistor X and connected to balancing resistor Y. The third network isthen balanced by adjustment of resistor Y, the balancing resistors W and X remaining at their settings which represent first assumed values of the variables represented thereby. This process is repeated, the construction of the switch S being such that it is moved from position 4 to position 1 when the error voltage becomes zero in the fourth network. If the equation represented by the original settings of the coefficients is solvable by the method of successive iteration, the assumed values of the variables reppresented by the settings of balancing resistors W, X, Y, and Z become closer to the actual solution each time the resistors are operated to balance their respective networks. Four or five cycles of operation are normally ample to provide a very accurate solution.

It will be apparent that the present computer offers a number of important advantages. time is efiected since the motors and relays operate much more rapidly than the human hand and errors in observation are eliminated. It will be noted that the speed of reversible motor 16 is proportional to the error voltage fed thereto. Accordingly, if the particular network being adjusted is badly out of balance, motor 16 operates rapidly to effect balance of the network through adjustment of one of the resistors W, X, Y, or Z. However, as the network approaches a balanced condition, the amplitude of the error signal decreases and the motor moves more slowly. This substantially contributes to the speed and accuracy of the solution obtained with this computer. The gearing device of Figures 2 to 4 operates very reliably and contributes substantially to the speed and accuracy with which the solutions to the equations are obtained.

A substantial saving in with a present, preferred embodiment thereof, it is to be understood that this description is illustrative only and is not intended to limit the invention, the scope of which is defined by the appended claims.

I claim:

1. In a gearing device for use in a computer which comprises, in combination, a driving shaft, a gear thereon, a plurality of variable resistors spaced around said driving shaft, a control shaft connected to each of said variable resistors, a slotted member constraining each variable resistor for movement thereof in a radial direction toward and away from said driving shaft, a gear on each control shaft, a spring urging each variable resistor radially outward from said driving shaft so that its gear is disengaged from the gear on said driving shaft, and electromagnetic means for moving each control shaft to engage the gear on said control shaft with the gear on said driving shaft.

2. A gearing device for use in a computer which comprises, in combination, a driving shaft, a gear thereon, a plurality of variable resistors spaced around said driving shaft, a control shaft connected to each of said variable resistors, a slotted member constraining each variable resistor for movement thereof in a radial direction toward and away from said driving shaft, a gear on each control shaft, a spring urging each variable resistor radially outward from said driving shaft so that its gear is disengaged from the gear on said driving shaft, an armature mounted on each variable resistor, and a coil mounted on said driving shaft for attracting said armature to move the gear on said control shaft into engagement with the gear on said driving shaft.

3. A gearing device comprising, in combination, a drive shaft, a motor coupled to said drive shaft, a plurality of variable impedance units spaced around said drive shaft, said impedance units being connected in the input circuit of said motor, and means for coupling said impedance units selectively to said drive shaft whereby rotation of said drive shaft varies the impedance of said unit coupled thereto.

4. A gearing device comprising, in combination, a drive shaft, a motor coupled to said drive shaft, a gear mounted on said drive shaft, a plurality of variable impedance units spaced around said drive shaft, said impedance units being connected in the input circuit of said motor, a separate control shaft connected to each of said impedance units, a gear on each of said control shafts, means urging each of said control shafts to positions wherein its gear is disengaged from the gear on said drive shaft, and means for moving each control shaft selectively to engage the gears on said control shafts with the gear on said drive shaft.

5. A gearing device comprising, in combination, a drive shaft, a gear on said drive shaft, 2. motor coupled to said drive shaft, a plurality of variable resistors spaced around said drive shaft, said variable resistors being connected in the input circuit of said motor, a separate control shaft connected to each of said resistors, a slotted member constraining each of said resistors for movement thereof in a radial direction toward and away from said drive shaft, a gear on each of said control shafts, a spring urging each variable resistor radially outward from said drive shaft so that its associated gear is disengaged from the gear on said drive shaft, and electromagnetic means for moving each of said control shafts selectively to engage the respective gears on said control shafts with the gear on said drive shaft.

6. A gearing device comprising, in combination, a drive shaft, a gear thereon, a motor coupled to said drive shaft, a plurality of variable resistors, spaced around said drive shaft, said variable resistors being connected in the input circuit of said motor, a separate control shaft connected to each of said resistors, a slotted member constraining each variable resistor for movement thereof in a radial direction toward and away from said drive shaft, a gear on each of said control shfts, a spring urging each variable resistor radially outward from said drive shaft so that its associated gear is disengaged from the gear on said drive shaft, an armature secured to each of said variable resistors, and a plurality of coils mounted on said drive shaft for attracting respective ones of said annatures to move the respective gears on said control shafts into engagement with the gear on said drive shaft whereby rotation of said drive shaft varies the resistance of the resistor coupled thereto.

References Cited in the file of this patent UNITED STATES PATENTS 

